Electrical generator



Feb. 6, 19:40. w. E. KOCK ET AL ELECTRICAL GENERATOR Original Filed Jan. 8, 1936 .5 5mm M W i TL m 0 VTN MMM wwwbmt i wi wk s m 1 a J" ATTORNEY Patented Feb. 6, 1940 UNITED STATES PATENT OFFlCE Ohio, assignors to The Baldwin cinnati, Ohio Company, Cin- Application January 8, 1936, se ial No. 58,153 Renewed August 12, 1939 4 Claims.

In the co-pending application Serial No.

' 7,0 1,173 of Winston E. Kock, filed December 6, 1933, Patent No. 2,046,463 issued July '7, 1936,

there was described a glow discharge oscillation generator of high stability, employing in a controlling circuit both a capacity and an inductance. In the co-pending application, Serial No.

16,449, of the same inventor, filed October 23,

1935, Patent No. 2,139,898 issued December 13,

1938, there was described an oscillating circuit having still greater stability and employing a glow discharge tube of the three element variety in which a part of the generated oscillation voltage was impressed on the grid of the tube to trigger the discharger. Also in the co-pending application of said Kock, Serial No. 53,955, filed December 11, 1935, Patent No. 2,128,367 issued August 30', 1938, it has been shown that by the use of a multiplicity of three electrode gas discharge tubes,it is possible to generate oscillations of related frequency in the circuits of the respective tubes, the frequency of several oscillating circuits being controlled by one master oscillator. For use, for example, in' an electrical organ, one of the tubes is arranged for stable oscillations at a comparatively high audio frequency. A part of the voltage of the first oscillating circuit is applied to the grid of the second tube in the series. Providing the constants for the second circuit are approximately adjusted for oscillation at a harmonically, related frequency, certain pulsations of the grid voltage derived from the first oscillating circuit will occur attimes when the condenser for the second circuit has been charged to or approximately to discharge potential. Such pulsations of the grid voltage will therefore operate to trigger the discharge of the second tube; and it will be clear that the frequency of the secondoscillating circuit is fixed at a value harmonically related to the frequency of the first. In a similar manner, another-oscillating circuit may be re- This gives a type of coordination and control in an electrical musical instrument very much superior to what is obtained when there is aseparate oscillating circuit for each note in the range of the instrument, each separate oscillating circuit having stabilization control unrelated tothat of any other circuit. Also because the first master oscillator in each circuit controls the frequency of those circuits connected with it, there is brought about a great simplification of apparatus and the necessary mechanism can be condensed in a very much smaller space.

It is an object of the present invention to make it unnecessary to provide a separate tube for each oscillating circuit. It is also an object of our invention to provide a new type of glow discharge device adapted for the simultaneous generation of a plurality of harmonically related frequencies. These and other objects of our invention which will be set forth hereinafter, or will be apparent to one skilled in the art upon reading these specifications, we accomplish by that certainconstruction and arrangement of parts of which we shall now describe an exemplary embodiment, both of tube and of circuit. I

Reference is now made to the drawing wherein special multi-electrode gas discharge tube which may be used for this purpose.

Fig. 2 indicates an exemplary circuit arrange.- ment for the generation of -a plurality of harmonically related frequencies and employing the tube of Fig. 1.

Briefiyin the practice of our inventiorze. we

provide a tube arranged in accordance with principles known inthe art, to act as a three electrode glow discharge tube,-i. e., the tube will have a cathode preferably of the indirectly heated type, a first grid to triggerthe discharge, and electrode means between which and the cathode the discharge mayoccur. Our tube differs from tubes hitherto produced however, in that there are a plurality, of electrodes related not only to the cathodeand the first grid, but also to each other. These electrodes excepting the final ones, are in the form of grids, so that they may act individually as plates or anodes in themselves, or as gridsrespecting'other electrodes in the series.

In the exemplary circuit, the cathode and the third electrode of the series act respectively as the cathode and anode for the first oscillating Fig. 1 shows somewhat diagrammatically, a

circuit comprising the cathode and the fourth electrode, and so on through the series, providing the elements following the third electrode are made parts of oscillating circuits whose constants permit oscillations at frequencies harmonically related to the frequency of the first or master oscillation circuit comprising the cathode, the first grid and the third electrode.

In Fig. 1 we have shown an exemplary form of glow discharge tube in which there is located within the usual envelope A, a cathode C preferably of the indirectly heated type and preferably coated with some emissive material. The leads of the various elements have been indicated in Fig. 1 by indicia corresponding to the elements themselves. If the cathode is an indirectly heated cathode, it will have filament leads I. A first grid G is related to the cathode. To this again there is a third element P1, which is in the form of a grid but is adapted to act both as a plate respecting the first oscillating circuit and as a grid respecting other related oscillating circuits. The numbers of elements beyond this point will vary with the desired use of the device. In Fig, 1 we have shown a fourth element P2 similar to the element P1, and a final element P3. This last element if it is the final one of the series does not need to be of grid-like form because it does not serve as a grid for succeeding elements. It therefore may be in the form of a plate. The tube will have appropriate leads and current connection means, and will also have the proper atmosphere in the envelope A for glow discharge purposes, as is known in the art.

Referring to the circuit diagram, Fig. 2, the method of operation is as follows: The tube is represented as T, with C as the cathode, which may be either indirectly or directly heated, G as the true grid, and P1, P2 as the remaining grids which are to act as plates. The final surrounding plate is indicated at P3. The first three electrodes C, G and P1, operate as a standard hot cathode three electrode gas discharge tube, and are connected up as a grid coupled inductive glow discharge oscillator as described in the said patent of Winston E. Kock, No. 2,139,898. The frequency of these oscillations is determined by the inductance L and capac ty C1; secondary S1 applies some of the generated voltage to the grid G and secondary S2 furnishes the signal voltage to a circuit comprising the lead f1. Resistance R1 is used to set the oscillator at maximum stability.

The next electrode P2 is connected to the circu t comprising resistance R2 and capacity C2 the constants of which are chosen so as to effect a discharge between the plate P2 and cathode C at a freouency about half that of the frequency of the first described oscillating circuit. Thus every other time that the discharge occurs to plate P1 there will be a strong tendency for the discharge to extend all the way to plate P2 provided the voltage on the condenser C2 has built up to the proper value. (R5, the resistors which furn sh a small signal voltage. have low resistance, so that the voltage on the condenser C2 determines the voltage between plate P2 and the cathode.) This is accomplished by selecting the proper values of C2 and R2. In the same way R3 and C3 are selected to give a different subharmonic of the main oscillator section in a third oscillating circuit and this can be continued for as many additional signals as there are extra electrodes. Each of these electrodes cannot fire until the preceding electrode does, so that the main oscillator section controls the frequency of all the succeeding plate sections. Thus a simple means of obtaining a large number of subharmonies from one compact frequency generator is produced.

It is to be understood that the circuits and method of construction shown are simply examples and that the uses and construction are not limited to those specifically shown.

While we have described our apparatus in connection with an exemplary use in a musical instrument, it will be understood that our invention is not confined thereto, and that the tube and the various circuits which may be used with it are adapted for the generation of oscillations for any purpose for which they are desired, and also for the generation of oscillations at subaudio and super-audio frequencies, the frequencies harmonically related.

Modifications may, of course, be made in the form of our tube and the disposition of its elements, but it will be noted that with respect to any series of elements C, G, P1, P2, etc., the elements G, P1, etc., are not only related individually to the cathode C, but are also related to each other, so that the device is not com parable to tubes which merely have a common electrode for a plurality of discharge circuits. Were this done, there would have to be separate connections, probably external of the tube between the various sets of glow discharge electrodes and controlling means therefor, and'the number of elements in the tube would also be increased. While our invention does not preclude the location of as many series of the elements C, G, P1, P2, etc., in the same envelope as may be desired, yet each of the elements in each of the series will be individually related, as described herein.

Having thus described our invention, we claim:

1. An oscillation generator capable of simultaneously and separately producing a plurality of oscillations of different frequencies, said oscillation generator comprising a gas filled tube arranged to operate as a glow discharge oscillator and comprising a common cathode, a control grid and a third electrode, an oscillating circuit in which said elements are located to produce sustained oscillations of a given frequency, a fourth electrode in said tube, an oscillating circuit in which said common cathode and said fourth electrode are located to produce oscillations of a different but related frequency, said third electrode being perforated and related to said fourth electrode to act as a grid therefor and to affect the discharge in said second oscillating circuit at intervals which are harmonically related to the frequency intervals of the oscillations of said first oscillating circuit.

2. An oscillation generator capable of producing oscillations of different but related frequencies, said oscillation generator comprising a single gas filled tube arranged to operate as a glow discharge oscillator, and comprising a common cathode, a plurality of grid structures successively related thereto and a final plate structure related to said cathode through said grid structures, a first oscillating circuit comprising said cathode and the second grid, and containing capacity and inductance of values to produce oscillations at a desired frequency, said second grid acting as an anode for said oscillating circuit, and means for impressing upon the first grid variations of potential derived from said oscillat- I v 4. An oscillation generator capable of producing circuit, whereby said first grid acts as a stabilizer for said first mentioned oscillating circuit, and a plurality of additional oscillating circuits each comprising said common cathode and a successive electrode in said tube, successive grid structures excepting the first in said tube being arranged to act as an anode in one oscillating circuitand as a control grid in a succeeding oscillating circuit oscillating at a harmonically related frequency. I

3. An oscillation generator capable of producing oscillations of diiferent but related frequencies, comprising a gas filled tube arranged to operate as a glow discharge oscillator and including a common cathode, a second electrode and a third electrode related successively to said cathode, means for producing periodic glow discharges at a given frequency between said cathode and said second electrode, and a circuit including said cathode and said third electrode, arranged to produce periodic glow discharges between said cathode and said third electrode, at a frequency different from said given frequency, said second electrode being perforated and related to said third electrode so as to act as a grid therefor and to affect the discharges between said 1 cathode and said third electrode so that they oc: cur at a frequency which is harmonically related to said given frequency.

ing oscillations of difierent but related frequencies, comprising a single gas filled tube arranged to operate as a glow discharge oscillator i and including a common cathode, a-plurality of grid-like form and arranged so that each acts a an anode for the discharges taking place between it and said cathode and acts as a grid and affects the discharges taking place between said cathode and a succeeding electrode so that the discharges between said cathode and said succeeding electrodes occur at respective frequencies which are harmonically related to said given frequency.

' WINSTON E.u KOCK.

JOHN F. JORDAN. 

